Look at the state of that…
What we have here is a Photoflex light disk - I am sure along the way you have all seen these. They fold down to about 1/4 the full size. I went to use this particular one this morning and this is what I found. My vague recollection is that I used it about 3 months ago and nothing really bad happened to it while I was shooting. there may have been a tiny bit of light mist that day. It definitely was cloudy. I was shooting indoors that day and the exposure to the elements consisted of a trip from my trunk and back. I can tell you that none of my other gear suffered and it definitely was not soaking wet when I put it back with all my other crap.
I have had this particular disk along with 2 60" disks for about 8 years. Up until this they were all pretty decent and not even dirty. The sparkly sides of all of them is beginning to flake off where they get creased as they are folded but that's it. I never really thought about it before but these are definitely NOT the way to go if you do any kind of shooting or transportation that risks the slightest bit of moisture due to the steel frame that seems to disintegrate with any tiny bit of dampness.
I used to use California Sunbounce reflectors but about 5 of them got mislaid somewhere along the way. They are CRAZY expensive but I have shot with them in the rain, by the ocean, in the surf and can tell you personally they are 100 times more durable and have some other nice handling features as well. I guess I will have to save my pennies to replace them.
One other thing that you cannot see in the images - it also warped severely so it's not even flat anymore. Hmmm - I don't even want to speculate how that is related to moisture.